BSIM4 to PSP Model Conversion for Passive Mixer IM3 Simulation

BSIM4 model is not suitable for distortion analysis of circuits with bias point VDS = 0, such as passive mixers and RF switches, due to discontinuities in higher order derivatives. Surface potential based PSP model has continuous derivatives to at least third order, and is therefore suitable for intermodulation products simulation. This paper presents the BSIM4 to PSP model conversion flow and comparison of passive mixer simulation results. Simulation results show good agreement of original BSIM4 and converted PSP model CV, IV, compression point, conversion loss and noise figure, which validates the conversion flow. The converted model has a correct IM3 slope of 3, allowing the simulation of intermodulation products, which was not possible with the original BSIM4 model.